Sunday, October 26, 2008

Even More Beautiful Trees, and a Sequoia Story

The mini-meme on trees grew larger today when I wasn't looking....here are some more that I noticed when I got online tonight (in addition to the links mentioned in my previous post). I am really enjoying your contributions; it's great to see that we geologists can sometimes step back and appreciate the "overburden" that sometimes obscures our all-important outcrops. Of course, all these trees exist at the consent of geology, and I can't help but add some geological notes at the end of the post tonight...

Hypo-theses offers some beautiful tree shots from the Lake District in England (including some Norwegian pegmatite to keep things geological)

In short, the Sequoias have existed as a genus for 200 million years or more and once existed in groves across North America, Europe and Asia. The trees of Petrified Forest National Park were probably a related species, and I have this wonderful image in my mind of giant dinosaurs wandering among the giant trees. Today the genus exists only as 60 or so groves of Sequoia trees in the Sierra Nevada, as the coast redwoods in northern California, and as the Dawn Redwood in the smallest corner of China, in a single grove of no more than 5,000 trees that was only discovered in 1944, and described in 1948. It had been thought to be extinct in the Miocene epoch.

The Sequoias were apparently wiped out elsewhere by climate change, especially the Pleistocene ice ages, but in the Sierra, they survived, barely, by propogating up and down the gentle western slope of the mountains as the climate alternated between glacial and interglacial periods. Some pollen work suggests they may have been on the very verge of extinction, but luckily for us they survived, and now are appreciated as the largest living things on the planet. Nearly all of the existing groves are protected in National and State Parks, including the recently created Giant Sequoia National Monument.

I have ideas for two or three more blogs on the subject of trees and geology, but I have vigorously been avoiding the pile of grading in my living room, so keep watching later this week....thanks again to everyone for your contributions!

About Me

I am a teacher of geology at Modesto Junior College and former president of the National Association of Geoscience Teachers, Far Western Section. I have led field trips all over the western United States, and a few excursions overseas, but my homebase is the Sierra Nevada, the Great Valley, and the Coast Ranges of California.

Ask Geotripper

Is there something about geology that you are curious about? Do you have questions about the scientific aspects of political controversies? I can try to provide a scientist's perspective. Your questions and possible answers could be a springboard to a blog discussion, or they can be private. Anonymity is always assumed. Contact Geotripper at hayesg (at) mjc.edu.

Blooks, Boogers and Bleries

Here are some of the series I've produced for the Geotripper Blog:

The Other California: what to see when you've seen all the really famous places in the Golden State (in progress).Into the Great Unknown: A rafting journey down the Colorado River through the Grand Canyon. The most incredible adventure of my life (so far)!

The Hawai'i That Was: An exploration of the geology, natural history, and anthropology of the most isolated lands on the planet. It's a lot more than beaches, shopping, and palm trees!